The invention concerns a method for the automatic control of an internal combustion engine-generator unit.
DE 199 37 139 C1 describes a method for the automatic control of an internal combustion engine-generator unit, in which the speed of the internal combustion engine is monitored in a closed-loop speed control system. With the detection of a significant load change on the power takeoff of the internal combustion engine, the injection start is additionally shifted towards late in terms of smaller crankshaft angles before top dead center. A significant load change on the power takeoff is understood to mean, in the case of use in a ship, the broaching of the ship's propulsion unit and, in the case of generator operation, load rejection. The shift in the injection start is produced by special design of the injection start input-output map. The method cannot be applied to a load application.
DE 44 46 246 C2 describes a method for the closed-loop control of the load behaviour of an internal combustion engine-generator unit. In this method, when a load application is detected, the injection start is additionally shifted towards early for automatic speed control. This shift occurs as a function of the internal cylinder pressure or a manifold pressure of the exhaust turbocharger. However, the method is complicated with respect to adjustment.
In practice, the injection start input-output map for an internal combustion engine generator application is adjusted in the region of the steady-state speed in test stand tests. The steady-state speed corresponds to a speed value of 1,500 rpm in a 50-Hz application and a speed value of 1,800 rpm in a 60-Hz application. The speed values below this steady-state speed are associated with early injection start values in the input-output map. These early injection starts are intended to counteract the speed drop when a load is applied. This results in the problem that these speed values and these injection start values are also passed through during the run-up of the internal combustion engine-generator unit. Since these values are not optimum, unfavorable operating values of the internal combustion engine are realized. In addition, the run-up time from the start-up of the internal combustion engine to the rated speed can be prolonged. Another problem that arises in an internal combustion engine-generator unit that is operated with a power level according to a desired speed adjustment is that the injection start is not shifted towards early until the speed has already dropped significantly, so that the effect of the shift in the injection start is very small.